Dogs are susceptible to contagious yawning just like people, says an article in Animal Cognition, but only after they get older. Dogs, like humans, show a gradual development of susceptibility to contagious yawning and the new paper says dogs catch yawns from humans. But Only dogs above seven months of age catch these human yawns - younger dogs are immune to the contagion.

Contagious yawning has been researched in humans, adult chimpanzees, baboons and dogs, some speculate it can be used as a measure of empathy. Empathy, mimicking the emotional responses of others, is difficult to measure directly, but contagious yawning allows assessment of a behavioral empathetic response, the Swedish researchers say.

Elainie Alenkær Madsen, PhD, and Tomas Persson, PhD, of the Cognitive Zoology Group at Lund University, engaged 35 dogs in Denmark, aged between four and 14 months, in bouts of play and cuddling and observed the dogs' responses when a human repeatedly yawned or gaped or performed neither of the two expressions. Only dogs above seven months of age showed evidence of contagious yawning. They note this pattern of development is consistent with that in humans, who also show a developmental increase in susceptibility to yawn contagion, beginning to yawn contagiously at the age of four, when a number of cognitive abilities, such as accurate identification of others' emotions, begin to clearly manifest. One interpretation that Madsen and Persson suggest is that the results reflect a general developmental pattern, shared by humans and other animals, in terms of affective empathy and the ability to identify others' emotions. Given that contagious yawning may be an empathetic response, the results suggest that empathy and the mimicry that may underlie it develop slowly over the first year of a dog's life.

The researchers say they may have transferred the emotion that yawning reflects (sleepiness) to the dogs, as nearly half of the dogs responded to yawning with a reduction in arousal, to the extent that the experimenter needed to prevent a number of dogs from falling asleep.

Research with adult humans and other primates suggest that individuals are more likely to yawn contagiously to those with whom they have close emotional bonds. Madsen and Persson tested the dogs with both an unfamiliar experimenter and their owner, but found no evidence that the puppies preferentially yawned in response to the yawns of the human with whom they were emotionally close. Since this is also the case for young human children, the researchers suggest that in species that show an empathy-based social modulatory effect on contagious yawning, this behavior only emerges at later stages of development.